Definition of "once-in-a-lifetime" [once-in-a-lifetime]

• That is likely to happen only once in one's lifetime. (adjective)

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• "Snow is even predicted to fall on the hills around Auckland, 660km to the north, in what the MetService is describing as a once-in-a-lifetime storm."
• "Wearing a tie and button-down shirt with his sleeves rolled up, the president began by referring to the "once-in-a-lifetime economic crisis" facing the nation, saying his administration knew "it was going to take years" to rebuild."
• "Rappers Melle Mel and Scorpio, part of the Furious Five, joined Grandmaster Flash on the Grammy stage Wednesday to perform the iconic song, "The Message," along with Lupe Fiasco, Common and LL Cool J, an experience that the DJ described as "once-in-a-lifetime.""